fix(packaging): expose Ajv from CJS validator subpaths

[morluto]

Summary

Fixes the CommonJS validators/ajv subpath export for both @modelcontextprotocol/server and @modelcontextprotocol/client. In CommonJS consumers, reading Ajv from either AJV validator subpath currently throws ReferenceError: import_ajv is not defined.

The CJS build was preserving Ajv as a live getter but leaving it pointed at an ESM-only local alias (import_ajv). Exporting Ajv as a concrete local value from the provider makes the generated CJS subpath re-export require_ajvProvider.Ajv, matching the actual CJS provider module.

Adds regression coverage through the existing dist/barrel tests by requiring the built CJS validator subpath and constructing Ajv, addFormats, and AjvJsonSchemaValidator.

Fixes #2430.

Verification

• pnpm --filter @modelcontextprotocol/server --filter @modelcontextprotocol/client build
• node -e "const m = require('./packages/server/dist/validators/ajv.cjs'); new m.Ajv({ strict: false })"
• node -e "const m = require('./packages/client/dist/validators/ajv.cjs'); new m.Ajv({ strict: false })"
• pnpm --filter @modelcontextprotocol/server test -- test/server/barrelClean.test.ts
• pnpm --filter @modelcontextprotocol/client test -- test/client/barrelClean.test.ts
• pnpm --filter @modelcontextprotocol/core-internal test -- test/validators/validators.test.ts
• node scripts/smoke-dist-types.mjs
• git diff --check

[changeset-bot]

🦋 Changeset detected

Latest commit: c269c39

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@modelcontextprotocol/server	Patch
@modelcontextprotocol/client	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

Open in StackBlitz

@modelcontextprotocol/client

npm i https://pkg.pr.new/@modelcontextprotocol/client@2431

@modelcontextprotocol/codemod

npm i https://pkg.pr.new/@modelcontextprotocol/codemod@2431

@modelcontextprotocol/core

npm i https://pkg.pr.new/@modelcontextprotocol/core@2431

@modelcontextprotocol/server

npm i https://pkg.pr.new/@modelcontextprotocol/server@2431

@modelcontextprotocol/server-legacy

npm i https://pkg.pr.new/@modelcontextprotocol/server-legacy@2431

@modelcontextprotocol/express

npm i https://pkg.pr.new/@modelcontextprotocol/express@2431

@modelcontextprotocol/fastify

npm i https://pkg.pr.new/@modelcontextprotocol/fastify@2431

@modelcontextprotocol/hono

npm i https://pkg.pr.new/@modelcontextprotocol/hono@2431

@modelcontextprotocol/node

npm i https://pkg.pr.new/@modelcontextprotocol/node@2431

commit: c269c39